Spatio-temporal inequalities in vulvar cancer mortality in Spain, 1999-2023: a nationwide Bayesian analysis

To conduct the first nationwide spatio-temporal analysis of vulvar cancer mortality in Spain, identifying geographical inequalities and temporal trends over 25 years.

A population-based ecological study analyzed mortality data (1999-2023) across 52 Spanish provinces and autonomous cities. Expected deaths were calculated via indirect standardization. Hierarchical Bayesian spatio-temporal models were implemented using Integrated Nested Laplace Approximation (INLA).

Spatial heterogeneity accounted for 68.8% of the total posterior variance, whereas the national temporal trend explained only 8.2%. Nationally, mortality risk showed a modest downward trend, with the RR decreasing from 1.054 (95% CrI 0.981-1.133) in 1999 to 0.954 (95% CrI 0.890-1.022) in 2023. However, areas with a high posterior probability (PP(RR > 1) > 0.95) of excess mortality were consistently identified in southwestern Spain (Badajoz RR 1.25, Cádiz 1.21, Huelva 1.20, Sevilla 1.18) and Lugo (RR 1.16), while lower risks were observed in Madrid and Barcelona (RR 0.85).

Vulvar cancer mortality in Spain shows persistent geographical disparities rather than a uniform national trend. These ecological findings do not allow causal interpretation, but they may reflect underlying contextual factors, such as socioeconomic inequalities, heterogeneous access to early diagnosis, variability in access to specialized gynecologic oncology services, and differences in the detection and management of precursor conditions. These results highlight the need for further research incorporating incidence, clinical stage, and healthcare access data, as well as public health strategies aimed at ensuring equitable access to multidisciplinary care and strengthening coordinated early detection pathways across regions.